Technical Abstract:
Straighthead is a physiological disease of rice resulting in sterile panicles and the exact cause of straighthead is unknown. Nineteen cultivars rated from resistant to susceptible to straighthead were studied in 2004 in 3 environments; clean soil with no straighthead history, monosodium methanearsonate (MSMA) treated soil for inducing straighthead, and a farm field with straighthead history. Correlation was analyzed on cultivar mean derived from 12 observations. Grain yield was greatly reduced (r=-0.6), and maturity was delayed (r=0.5) by straighthead. Severe straighthead was significantly associated with less content of S (r=-0.5) and Cu (r=-0.6) in flag leaves. Other correlations such as straighthead with P, K, Ca, Mg, Na, Fe, Mn, Zn, and B were not significant in this study.